A wind turbine emergency shutdown working condition load optimization method and system

Abstract

The application discloses a kind of wind turbine emergency shutdown operating condition load optimization method and system, the method is the relationship between segmented pitch rate and wind energy utilization rate under wind turbine emergency shutdown operating condition is analyzed, based on wind energy utilization rate Cp New segmented pitch curve is defined, simulation evaluates multiple segmented pitch curves Hub_Myz load or TowerTop_Mxy load, select the segmented pitch curve corresponding to the minimum load as the optimal segmented pitch curve, then applied in wind turbine to realize load optimization under emergency shutdown operating condition;The application can greatly reduce the ultimate bending moment load of wind wheel, transmission chain, yaw system and tower top, at the same time, the application is based on pitch logic to realize the load reduction and cost reduction of wind turbine major components, without adding any new hardware, and the scope of application is wider, with economy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine load optimization, in particular to a wind turbine emergency shutdown operating condition load optimization method and system. BACKGROUND

[0002] The wind turbine is a power machine for converting wind energy into electric energy. It captures wind energy through the rotation of the wind wheel and connects the generator through the mechanical transmission device to realize the function of converting kinetic energy into electric energy. In recent years, with the rapid development of the wind power industry, the single machine capacity and the diameter of the wind wheel of the wind turbine have gradually increased, the component load of the wind turbine has increased year by year, and the weight of the components of the wind turbine has gradually increased. Therefore, if efficient load optimization is achieved, it is a key factor to ensure the structural safety of the wind turbine and reduce the cost.

[0003] With the development of large-scale and lightweight requirements of the wind turbine, the limit load of the wind turbine gradually increases. Based on the IEC61400-1 standard, the design stage of the wind turbine needs to evaluate: normal power generation operating condition, fault operating condition, normal shutdown operating condition, emergency shutdown operating condition, starting operating condition, and idling operating condition. Among them, the fault operating condition and the emergency shutdown operating condition are two key operating conditions that affect the limit load of the wind turbine, and the severe sub-condition involves the "emergency shutdown of the feathering action". Therefore, how to optimize the "emergency shutdown of the feathering action" becomes an important way to optimize the limit load of the two types of operating conditions.

[0004] In order to optimize the "emergency shutdown of the feathering action", it is necessary to analyze the relationship between the "segmented feathering rate" and the "wind energy utilization rate" (Cp). If the "segmented feathering rate" causes the "wind energy utilization rate" to appear mutations, such as "peak" and "valley", it is easy to cause the "aerodynamic load" of the wind wheel to fluctuate, and ultimately cause the limit bending moment of the wind wheel to increase. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a wind turbine emergency shutdown operating condition load optimization method and system. A new segmented feathering curve is defined based on the wind energy utilization rate Cp to realize the smooth decline of the wind turbine wind energy capture under the emergency shutdown operating condition and achieve the purpose of significantly reducing the limit bending moment of the wind wheel.

[0006] The purpose of the present application is achieved by the following technical scheme: a wind turbine emergency shutdown operating condition load optimization method, comprising the following steps:

[0007] S1, according to the single segment feathering rate of the wind turbine, simulating the rotating hub coordinate system Hub_Myz load or the tower top coordinate system TowerTop_Mxy load of the wind turbine under the corresponding single segment feathering rate, selecting the single segment feathering rate corresponding to the minimum load as the reference feathering rate;

[0008] S2, simulate and obtain three-dimensional matrix table of wind energy utilization rate Cp, pitch angle PitchAngle and tip speed ratio λ of the wind turbine, view the wind speed and rotor speed of the maximum value position of Hub_Myz load or TowerTop_Mxy load, and calculate the reference tip speed ratio λ0; according to the reference tip speed ratio λ0, the wind energy utilization rate-pitch angle Cp-PitchAngle curve is obtained in the three-dimensional matrix table;

[0009] S3, based on the Cp-PitchAngle curve, the Cp-PitchAngle derivative curve is obtained by derivation;

[0010] S4, according to the pitch angle PitchAngle of the maximum value position of Hub_Myz load or TowerTop_Mxy load, the pitch angle ±25deg region selection is carried out, which is the key pitch region, and the remaining region is the non-key pitch region;

[0011] S5, based on the reference pitch rate and the Cp-PitchAngle derivative curve, the reference pitch rate curve is calculated, and the data point number selection is carried out on the reference pitch rate curve according to the key pitch region and the non-key pitch region, to obtain the reference segmented pitch curve;

[0012] S6, according to the reference segmented pitch curve, the preset step and range are set by using the DOE method, and a plurality of segmented pitch curves are calculated;

[0013] S7, simulate and evaluate the Hub_Myz load or TowerTop_Mxy load of the plurality of segmented pitch curves, select the segmented pitch curve corresponding to the minimum load as the optimal segmented pitch curve, and then apply it to the wind turbine to realize load optimization under emergency shutdown working condition.

[0014] Further, the step S1 comprises:

[0015] According to the single segmented pitch rate of the wind turbine, the rotating hub coordinate system Hub_Myz load or the tower coordinate system top TowerTop_Mxy load of the wind turbine under the corresponding single segmented pitch rate is simulated by using software, the maximum Hub_Myz load or the maximum TowerTop_Mxy load of the wind turbine under emergency shutdown working condition is simulated and evaluated, and according to the preset load optimization requirement, the single segmented pitch rate corresponding to the minimum load is selected as the reference pitch rate.

[0016] Further, the step S2 comprises:

[0017] Simulate and obtain the three-dimensional matrix table of the wind energy utilization rate Cp, pitch angle PitchAngle and tip speed ratio λ of the wind turbine, view the wind speed and rotor speed of the maximum value position of Hub_Myz load or TowerTop_Mxy load in the three-dimensional matrix table, and obtain the rotor circumference, calculate the reference tip speed ratio λ0, as shown in the following formula:

[0018] λ0 = rotor speed × rotor circumference / wind speed

[0019] According to the reference tip speed ratio λ0, the wind energy utilization rate-pitch angle Cp-PitchAngle curve is obtained in the three-dimensional matrix table.

[0020] Further, the step S3 comprises:

[0021] Based on the Cp-PitchAngle curve, the derivative is obtained to obtain the Cp-PitchAngle derivative curve, and the absolute value of the ordinate of the Cp-PitchAngle derivative curve is taken.

[0022] Further, the step S5 comprises:

[0023] S5.1, using the reference pitch rate as the mean value of the reference segmented pitch rate;

[0024] S5.2, calculate the reciprocal of the Cp-PitchAngle derivative curve after taking the absolute value of the ordinate, obtain 1 / Cp-PitchAngle curve;

[0025] S5.3, divide the 1 / Cp-PitchAngle curve by the mean value of the 1 / Cp-PitchAngle curve to calculate the coefficient of the reference segmented pitch rate;

[0026] S5.4, multiply the mean value of the reference segmented pitch rate by the coefficient of the reference segmented pitch rate to obtain the reference pitch rate curve;

[0027] S5.5, according to the key pitch area and the non-key pitch area, the data point number of the reference pitch rate curve is selected, so that the key pitch area contains 4-6 data points, and the data point number of the non-key pitch area is simplified, to obtain the reference segmented pitch curve.

[0028] A wind turbine emergency shutdown working condition load optimization system is used to realize the wind turbine emergency shutdown working condition load optimization method, comprising:

[0029] a reference pitch rate acquisition module, according to a single-section pitch rate of a wind turbine, simulating a Hub_Myz load of a rotating hub coordinate system or a TowerTop_Mxy load of a tower coordinate system of the wind turbine under the corresponding single-section pitch rate, and selecting a single-section pitch rate corresponding to a minimum load as the reference pitch rate;

[0030] a reference tip speed ratio calculation module, simulating and acquiring a three-dimensional matrix table of a wind energy utilization rate Cp, a pitch angle PitchAngle and a tip speed ratio λ of the wind turbine, checking a wind speed and a rotor speed at a maximum value position of the Hub_Myz load or the TowerTop_Mxy load, and calculating a reference tip speed ratio λ0;

[0031] a Cp-PitchAngle curve acquisition module, according to the reference tip speed ratio λ0, acquiring a Cp-PitchAngle curve in the three-dimensional matrix table;

[0032] a Cp-PitchAngle derivative curve calculation module, based on the Cp-PitchAngle curve, deriving to obtain a Cp-PitchAngle derivative curve;

[0033] a key pitch region calculation module, according to the pitch angle PitchAngle at the maximum value position of the Hub_Myz load or the TowerTop_Mxy load, selecting a region of ±25 deg of the pitch angle as a key pitch region, and selecting a remaining region as a non-key pitch region;

[0034] a reference segmented pitch curve calculation module, based on the reference pitch rate and the Cp-PitchAngle derivative curve, calculating a reference pitch rate curve, and according to the key pitch region and the non-key pitch region, selecting a number of data points of the reference pitch rate curve to obtain a reference segmented pitch curve;

[0035] an optimal segmented pitch curve acquisition module, according to the reference segmented pitch curve, setting a preset step and range by using a DOE method, calculating a plurality of segmented pitch curves, simulating and evaluating Hub_Myz loads or TowerTop_Mxy loads of the plurality of segmented pitch curves, and selecting a segmented pitch curve corresponding to a minimum load as an optimal segmented pitch curve.

[0036] Further, the reference pitch rate acquisition module comprises:

[0037] According to the single-section pitch rate of the wind turbine, the Hub_Myz load in the rotating hub coordinate system or the TowerTop_Mxy load in the tower coordinate system of the wind turbine under the corresponding single-section pitch rate is simulated, the maximum Hub_Myz load or the maximum TowerTop_Mxy load of the wind turbine under the emergency shutdown working condition is evaluated, and according to the preset load optimization requirement, the single-section pitch rate corresponding to the minimum load is selected as the reference pitch rate.

[0038] Further, the reference tip speed ratio calculation module comprises:

[0039] The wind energy utilization rate Cp, the pitch angle PitchAngle and the tip speed ratio λ of the wind turbine are simulated and obtained, the wind speed and the rotor speed at the maximum Hub_Myz load or TowerTop_Mxy load are obtained in the three-dimensional matrix table, the rotor circumference is obtained, and the reference tip speed ratio λ0 is calculated, as shown in the following formula:

[0040] λ0 = rotor speed × rotor circumference / wind speed.

[0041] Further, the Cp-PitchAngle derivative curve calculation module comprises:

[0042] Based on the Cp-PitchAngle curve, the Cp-PitchAngle derivative curve is obtained by derivation, and the absolute value of the ordinate of the Cp-PitchAngle derivative curve is taken.

[0043] Further, the reference segmented pitch curve calculation module comprises:

[0044] 1) the reference pitch rate is used as the mean value of the reference segmented pitch rate;

[0045] 2) the reciprocal of the Cp-PitchAngle derivative curve after taking the absolute value of the ordinate is calculated to obtain the 1 / Cp-PitchAngle curve;

[0046] 3) the 1 / Cp-PitchAngle curve is divided by the mean value of the 1 / Cp-PitchAngle curve to calculate the coefficient of the reference segmented pitch rate;

[0047] 4) the mean value of the reference segmented pitch rate is multiplied by the coefficient of the reference segmented pitch rate to obtain the reference pitch rate curve;

[0048] 5) according to the key pitch area and the non-key pitch area, the number of data points of the reference pitch rate curve is selected, so that the key pitch area contains 4-6 data points, and the number of data points of the non-key pitch area is simplified to obtain the reference segmented pitch curve.

[0049] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0050] 1. The present application is a limit load optimization method based on the change curve of wind energy utilization rate Cp of a wind turbine, which can greatly reduce the limit bending moment load of the wind wheel, transmission chain, yaw system and tower top.

[0051] 2. The present application realizes load reduction and cost reduction of large components of a wind turbine based on the pitch logic, without the need to add any new hardware, which is low in cost and economical.

[0052] 3. The present application is suitable for a variable-pitch wind turbine, which has a wide application range and great popularization significance. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a schematic diagram of a wind turbine in a rotating hub coordinate system.

[0054] Figure 2 is a schematic diagram of a wind turbine in a tower coordinate system.

[0055] Figure 3 is a schematic diagram of the derivative curve of Cp-PitchAngle.

[0056] Figure 4 is a schematic diagram of the derivative curve of Cp-PitchAngle after taking the absolute value of the ordinate.

[0057] Figure 5 is a schematic diagram of a reference segmented pitch curve. DETAILED DESCRIPTION

[0058] The present application will be further described below in combination with specific embodiments.

[0059] Embodiment 1

[0060] The wind turbine emergency shutdown working condition load optimization method provided in the present embodiment includes the following steps:

[0061] S1, referring to Figures 1 to 2As shown, according to the single-section pitch rate of the wind turbine, the FAST software is used to simulate the Hub_Myz load in the rotating hub coordinate system or the TowerTop_Mxy load in the tower coordinate system under the corresponding single-section pitch rate, the single-section pitch rate is set to be 0.5 deg / s-9 deg / s, the maximum load of Hub_Myz or the maximum load of TowerTop_Mxy under the emergency shutdown working condition of the wind turbine is simulated and evaluated, and a reference pitch rate screening table is obtained, as shown in Table 1 below; at the same time, according to the preset load optimization requirement, the single-section pitch rate 1.5 deg / s corresponding to the minimum load is selected as the reference pitch rate;

[0062] Serial number Single-stage reeling rate (deg / s) Hub_Myz (kNm) TowerTop_Mxy (kNm) Minimum load 1 0.5 35383 27865 No 2 1 33275 26384 No 3 1.5 31052 24897 Yes 4 2 32987 25896 No 5 2.5 36783 28741 No 6 3 38974 30876 No 7 3.5 40762 32785 No 8 4 41824 34286 No 9 4.5 43891 36831 No 10 5 46914 38402 No 11 5.5 49120 40219 No 12 6 51247 43818 No 13 6.5 53439 46813 No 14 7 56895 49214 No 15 7.5 58129 52121 No 16 8 63012 55310 No 17 8.5 67126 58914 No 18 9 71025 64128 No

[0063] Table 1 reference pitch rate screening table

[0064] S2, the FAST software is used to simulate and obtain the three-dimensional matrix table of the wind energy utilization rate Cp, the pitch angle PitchAngle and the tip speed ratio λ of the wind turbine, the wind speed and the rotor speed at the maximum value position of the Hub_Myz load or the TowerTop_Mxy load are viewed, and the reference tip speed ratio λ0 is calculated, as shown in the following formula:

[0065] λ0 = rotor speed × rotor circumference / wind speed;

[0066] According to the reference tip speed ratio λ0, the wind energy utilization rate-pitch angle Cp-PitchAngle curve is obtained in the three-dimensional matrix table;

[0067] S3, referring to Figure 3 As shown, based on the Cp-PitchAngle curve, the Cp-PitchAngle derivative curve is obtained by derivation; referring to Figure 4 As shown, for the convenience of statistical segmented pitch rate, the absolute value of the ordinate of the Cp-PitchAngle derivative curve is taken;

[0068] S4, according to the pitch angle PitchAngle at the maximum value position of the Hub_Myz load or the TowerTop_Mxy load, the pitch angle ±25deg region selection is carried out, that is, 10deg-60deg is taken as the key pitch region, and the remaining region is taken as the non-key pitch region;

[0069] S5, based on the reference pitch rate and the Cp-PitchAngle derivative curve, the reference pitch rate curve is calculated, the data point number selection of the reference pitch rate curve is carried out according to the key pitch region and the non-key pitch region, and the reference segmented pitch curve is obtained, including:

[0070] S5.1, adopt the benchmark pitchback rate 1.5 deg / s as the mean value of the benchmark segmented pitchback rate;

[0071] S5.2, calculate the reciprocal of the Cp-PitchAngle derivative curve after taking the absolute value of the longitudinal coordinate, to obtain the 1 / Cp-PitchAngle curve;

[0072] S5.3, divide the 1 / Cp-PitchAngle curve by the mean value of the 1 / Cp-PitchAngle curve to obtain the coefficient of the benchmark segmented pitchback rate;

[0073] S5.4, multiply the mean value of the benchmark segmented pitchback rate by the coefficient of the benchmark segmented pitchback rate to obtain the benchmark pitchback rate curve;

[0074] S5.5, since the benchmark segmented pitchback rate contains 6-10 data points, the number of data points of the benchmark pitchback rate curve needs to be selected according to the key pitchback area and the non-key pitchback area, so that the key pitchback area contains 4-6 data points, and the number of data points in the non-key pitchback area is simplified, and each non-key pitchback area only contains 1-2 data points, thereby obtaining the benchmark segmented pitchback curve, as shown in Figure 5 ;

[0075] S6, according to the benchmark segmented pitchback curve, the DOE method is adopted to set the range to be 0.7-1.3 with a step size of 0.05, and 13 segmented pitchback curves are calculated;

[0076] S7, simulate and evaluate the Hub_Myz load or TowerTop_Mxy load of the 13 segmented pitchback curves, select the segmented pitchback curve corresponding to the minimum load as the optimal segmented pitchback curve, and then apply it to the wind turbine to realize load optimization under the emergency shutdown working condition.

[0077] Embodiment 2

[0078] The embodiment discloses a wind turbine emergency shutdown working condition load optimization system for realizing the wind turbine emergency shutdown working condition load optimization method of embodiment 1, comprising:

[0079] The benchmark pitchback rate acquisition module simulates the rotating hub coordinate system Hub_Myz load or the tower top coordinate system TowerTop_Mxy load of the wind turbine under the corresponding single-stage pitchback rate according to the single-stage pitchback rate of the wind turbine, and selects the single-stage pitchback rate corresponding to the minimum load as the benchmark pitchback rate;

[0080] A reference tip speed ratio calculation module simulates and obtains a three-dimensional matrix table of a wind energy utilization rate Cp, a pitch angle PitchAngle and a tip speed ratio λ of the wind turbine, views a wind speed and a rotor speed at a maximum value position of the Hub_Myz load or the TowerTop_Mxy load, and calculates a reference tip speed ratio λ0;

[0081] A Cp-PitchAngle curve acquisition module acquires a wind energy utilization rate-pitch angle Cp-PitchAngle curve corresponding to the reference tip speed ratio λ0 in the three-dimensional matrix table.

[0082] A Cp-PitchAngle derivative curve calculation module derives the Cp-PitchAngle curve to obtain a Cp-PitchAngle derivative curve.

[0083] A key pitch region calculation module selects a pitch angle ± 25 deg region as a key pitch region according to the pitch angle PitchAngle at the maximum value position of the Hub_Myz load or the TowerTop_Mxy load, and selects a remaining region as a non-key pitch region.

[0084] A reference segmented pitch curve calculation module calculates a reference pitch rate curve based on the reference pitch rate and the Cp-PitchAngle derivative curve, and selects data points of the reference pitch rate curve according to the key pitch region and the non-key pitch region to obtain a reference segmented pitch curve.

[0085] An optimal segmented pitch curve acquisition module sets a preset step and range by using a DOE method according to the reference segmented pitch curve, calculates a plurality of segmented pitch curves, simulates and evaluates Hub_Myz loads or TowerTop_Mxy loads of the plurality of segmented pitch curves, and selects a segmented pitch curve corresponding to a minimum load as an optimal segmented pitch curve.

[0086] Embodiment 3

[0087] The embodiment discloses a non-transitory computer readable medium storing instructions, when the instructions are executed by a processor, the steps of the wind turbine emergency shutdown working condition load optimization method according to embodiment 1 are executed.

[0088] The non-transitory computer readable medium in the embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a U disk, a mobile hard disk and the like.

[0089] Embodiment 4

[0090] The embodiment discloses a computing device, comprising a processor and a memory for storing a program executable by the processor, wherein the processor implements the wind turbine emergency shutdown working condition load optimization method according to the embodiment 1 when executing the program stored in the memory.

[0091] The computing device described in the embodiment can be a desktop computer, a notebook computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC) or other terminal device with a processor function.

[0092] The above-mentioned embodiments are only the preferred embodiments of the present application, and are not intended to limit the scope of the present application. Any changes made according to the shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for optimizing loads in emergency shutdown conditions of a wind turbine generator system, characterized in that: The following steps are involved: S1. According to the single-stage retraction rate of the wind turbine, simulate the rotating hub coordinate system Hub_Myz load or the tower coordinate system top TowerTop_Mxy load of the wind turbine at the corresponding single-stage retraction rate, and select the single-stage retraction rate corresponding to the minimum load as the benchmark retraction rate; S2. Simulate and obtain a three-dimensional matrix table of wind energy utilization factor Cp, pitch angle PitchAngle, and blade tip speed ratio λ of the wind turbine, check the wind speed and rotor speed at the maximum value of the Hub_Myz load or TowerTop_Mxy load, and calculate the reference blade tip speed ratio λ0; based on the reference blade tip speed ratio λ0, obtain the corresponding wind energy utilization factor-pitch angle Cp-PitchAngle curve in the three-dimensional matrix table; S3. Based on the Cp-PitchAngle curve, derive the Cp-PitchAngle derivative curve; S4. Based on the pitch angle PitchAngle at the maximum position of the Hub_Myz load or the TowerTop_Mxy load, select an area within ±25 degrees of the pitch angle as the critical return propeller area, and the remaining areas as non-critical return propeller areas; S5. Calculate a reference rewind rate curve based on the reference rewind rate and the Cp-PitchAngle derivative curve, select the number of data points for the reference rewind rate curve according to the key rewind area and the non-key rewind area, and obtain a reference segmented rewind curve; S6. According to the reference segmented propeller retraction curve, a preset step size and range are set using the DOE method to calculate and obtain multiple segmented propeller retraction curves; S7. Simulate and evaluate the Hub_Myz load or TowerTop_Mxy load of multiple segmented retraction curves, select the segmented retraction curve corresponding to the minimum load as the optimal segmented retraction curve, and then apply it to the wind turbine to achieve load optimization under emergency shutdown conditions.

2. A method for optimizing loads in emergency shutdown conditions of a wind turbine generator set according to claim 1, characterized in that: The step S1 comprises: According to the single-stage retraction rate of the wind turbine, software is used to simulate the rotating hub coordinate system Hub_Myz load or the tower coordinate system top TowerTop_Mxy load of the wind turbine under the corresponding single-stage retraction rate. The maximum load of Hub_Myz or the maximum load of TowerTop_Mxy of the wind turbine under emergency shutdown conditions is simulated and evaluated. At the same time, according to the preset load optimization requirements, the single-stage retraction rate corresponding to the minimum load is selected as the benchmark retraction rate.

3. The method for optimizing load of a wind turbine in emergency shutdown condition according to claim 1, characterized in that: The step S2 comprises: Use software simulation to obtain a three-dimensional matrix table of the wind turbine's wind energy utilization factor Cp, pitch angle PitchAngle, and tip speed ratio λ. In the three-dimensional matrix table, view the wind speed and rotor speed at the maximum value of the Hub_Myz load or TowerTop_Mxy load, obtain the rotor circumference, and calculate the reference tip speed ratio λ0, as shown in the following formula: λ0 = rotor speed × rotor circumference / wind speed; According to the reference tip speed ratio λ0, a corresponding wind energy utilization rate-pitch angle Cp-PitchAngle curve is obtained in the three-dimensional matrix table.

4. A method for optimizing loads in emergency shutdown conditions of a wind turbine generator set according to claim 1, characterized in that: The step S3 comprises: Based on the Cp-PitchAngle curve, a derivative of the Cp-PitchAngle curve is obtained by performing a derivation, and the absolute value of the ordinate of the derivative of the Cp-PitchAngle curve is obtained.

5. The method for optimizing load of a wind turbine in emergency shutdown condition according to claim 1, characterized in that: The step S5 comprises: S5.

1. Use the reference propeller retraction rate as the mean of the reference segmented propeller retraction rates. S5.

2. Calculate the reciprocal of the Cp-PitchAngle derivative curve after taking the absolute value of the ordinate to obtain the 1 / Cp-PitchAngle curve; S5.

3. Divide the 1 / Cp-PitchAngle curve by the mean of the 1 / Cp-PitchAngle curve to calculate a coefficient of the reference segmented retraction rate; S5.

4. Multiply the mean of the reference segmented propeller retraction rates by the coefficient of the reference segmented propeller retraction rate to obtain a reference propeller retraction rate curve. S5.

5. Select the number of data points for the reference propeller return rate curve based on the key propeller return area and the non-key propeller return area so that the key propeller return area contains 4-6 data points, and simplify the number of data points in the non-key propeller return area to obtain a reference segmented propeller return curve.

6. A wind turbine emergency shutdown load optimization system, characterized in that: A method for optimizing loads under emergency shutdown conditions of a wind turbine generator system according to any one of claims 1 to 5, comprising: The reference retraction rate acquisition module simulates the wind turbine's rotating hub coordinate system Hub_Myz load or tower coordinate system top TowerTop_Mxy load at the corresponding single-stage retraction rate according to the wind turbine's single-stage retraction rate, and selects the single-stage retraction rate corresponding to the minimum load as the reference retraction rate. The reference tip speed ratio calculation module simulates and obtains the three-dimensional matrix table of wind energy utilization factor Cp, pitch angle PitchAngle and tip speed ratio λ of the wind turbine, checks the wind speed and rotor speed at the maximum value of Hub_Myz load or TowerTop_Mxy load, and calculates the reference tip speed ratio λ0; The Cp-PitchAngle curve acquisition module obtains the wind energy utilization rate-pitch angle Cp-PitchAngle curve in the three-dimensional matrix table according to the reference blade tip speed ratio λ0; Cp-PitchAngle derivative curve calculation module, based on the Cp-PitchAngle curve, obtains the Cp-PitchAngle derivative curve by derivative; The critical propeller return area calculation module selects the area within ±25 degrees of the pitch angle as the critical propeller return area based on the pitch angle PitchAngle at the maximum position of the Hub_Myz load or TowerTop_Mxy load, and the remaining areas as non-critical propeller return areas; The benchmark segmented retraction curve calculation module calculates the benchmark retraction rate curve based on the benchmark retraction rate and the Cp-PitchAngle derivative curve, selects the number of data points for the benchmark retraction rate curve according to the key retraction area and the non-key retraction area, and obtains the benchmark segmented retraction curve; The optimal segmented propeller return curve acquisition module uses the DOE method to set the preset step size and range based on the benchmark segmented propeller return curve, and calculates multiple segmented propeller return curves; simulates and evaluates the Hub_Myz load or TowerTop_Mxy load of multiple segmented propeller return curves, and selects the segmented propeller return curve corresponding to the minimum load as the optimal segmented propeller return curve.

7. A wind turbine emergency shutdown load optimization system according to claim 6, characterized in that: The reference propeller retraction rate acquisition module includes: According to the single-stage retraction rate of the wind turbine, the rotating hub coordinate system Hub_Myz load or the tower coordinate system top TowerTop_Mxy load of the wind turbine under the corresponding single-stage retraction rate is simulated to evaluate the maximum load of Hub_Myz or the maximum load of TowerTop_Mxy of the wind turbine under emergency shutdown conditions. At the same time, according to the preset load optimization requirements, the single-stage retraction rate corresponding to the minimum load is selected as the benchmark retraction rate.

8. The wind turbine emergency shutdown load optimization system according to claim 6, characterized in that: The reference tip speed ratio calculation module includes: Simulate and obtain a three-dimensional matrix table of the wind turbine's wind energy utilization factor Cp, pitch angle PitchAngle, and tip speed ratio λ. In the three-dimensional matrix table, view the wind speed and rotor speed at the maximum value of the Hub_Myz load or TowerTop_Mxy load, obtain the rotor circumference, and calculate the reference tip speed ratio λ0, as shown in the following formula: λ0 = wind rotor speed × wind rotor circumference / wind speed.

9. The wind turbine emergency shutdown load optimization system according to claim 6, characterized in that: The Cp-PitchAngle derivative curve calculation module includes: Based on the Cp-PitchAngle curve, a derivative of the Cp-PitchAngle curve is obtained by performing a derivation, and the absolute value of the ordinate of the derivative of the Cp-PitchAngle curve is obtained.

10. The wind turbine emergency shutdown load optimization system according to claim 6, characterized in that: The reference segmented retraction curve calculation module includes: 1) The reference propeller retraction rate is used as the mean value of the reference segmented propeller retraction rate; 2) Calculate the inverse of the Cp-PitchAngle derivative curve after taking the absolute value of the ordinate to obtain the 1 / Cp-PitchAngle curve; 3) Divide the 1 / Cp-PitchAngle curve by the mean of the 1 / Cp-PitchAngle curve to calculate the coefficient of the benchmark segmented retraction rate; 4) Multiplying the mean of the reference segmented propeller return rate by the coefficient of the reference segmented propeller return rate to obtain a reference propeller return rate curve; 5) The number of data points of the benchmark retraction rate curve is selected according to the key retraction area and the non-key retraction area, so that the key retraction area contains 4-6 data points, and the number of data points in the non-key retraction area is simplified to obtain the benchmark segmented retraction curve.

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